CFRM options for duplexing in Db2 data sharing
The DUPLEX parameter options for the CFRM policy allow, enable, or disable duplexing of various structures for a Db2 data sharing group.
The following DUPLEX parameter options can be specified in the administrative data utility to specify the CFRM policy for duplexing of the group buffer pool, SCA, and lock. For more information, see CFRM parameters for administrative data utility.
| Parameter option | Valid for | Description |
|---|---|---|
DUPLEX(ENABLED) |
SCA, group buffer pool, lock | Automatically starts duplexing. For the CF structure, duplexing is started in synchronous mode. |
 DUPLEX(ENABLED,duplex-mode) |
Lock only |
Automatically starts duplexing, with the specified duplex mode. Possible duplex modes are
defined below. |
DUPLEX(ALLOWED) |
SCA, group buffer pool, lock | Allows duplexing. You must use a command to start duplexing. |
| DUPLEX(ALLOWED,duplex-mode) |
Lock only |
Allows duplexing, with the specified duplex mode. You must use a command to start duplexing.
Possible duplex modes are defined below. |
DUPLEX(DISABLED) |
SCA, group buffer pool, lock | Disables duplexing |
Possible values of
duplex-mode are:
- SYNCONLY
- The CF structure uses only synchronous duplexing. Either user-managed duplexing or system-managed synchronous duplexing is used. This is the default.
- ASYNCONLY
- The CF structure uses only asynchronous duplexing. System-managed asynchronous duplexing is
used.
When this keyword is used, system-managed duplexing rebuild allocation for the structure requires that the coupling facility level is CFLEVEL 21 or higher.
- ASYNC
- The structure uses asynchronous duplexing, if possible. If asynchronous duplexing is not possible, the structure uses synchronous duplexing. Some reasons that asynchronous duplexing is not possible are:
- The coupling facility level is less than CFLEVEL 21.
- There is no connector or application support for asynchronous duplexing.